You are correct. No rotor that is below minimum thickness is safe on any car for risk for hyper-extension of the caliper pistons.
As a matter of California state law, no parts company will turn a rotor that results in an undersized thickness.
Correct once again, since the resulting thickness after turning met the minimum thickness spec, it was permissible.
The results I experienced are excellent so far.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)